Method of reuse protection for lancet system

ABSTRACT

A lancet magazine for use in a lancing aid is described comprising a plurality of lancets each having a lancet body at the proximal end of the lancet and a lancet tip at the distal end of the lancet, where the proximal end of the lancet points in the direction of the proximal end of the housing of the lancet magazine and the distal end of the lancet is aligned in the direction of the distal end of the housing and the lancets in the unused state are completely surrounded by the housing. Furthermore, an extension unit is movably connected to the housing in such a manner that the housing can be extended by movement of the extension unit in the direction of the distal end of the housing such that the lancet is prevented from emerging from the lancet magazine.

RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 14/497,991, filed Sep. 26, 2014, which is a divisional applicationof U.S. application Ser. No. 13/210,795, filed Aug. 16, 2011, now U.S.Pat. No. 8,845,669, which is a continuation of International ApplicationPCT/EP2010/000876, filed Feb. 12, 2010, which claims priority to EP09002176.7, filed Feb. 17, 2009, all of which are hereby incorporatedherein by reference in their entirety.

BACKGROUND

The present invention relates to a lancet system in the form of a lancetmagazine which can be used in a lancing aid for collecting blood fordiagnostic purposes.

In a variety of diseases it is necessary to examine human blood for ananalyte contained therein. In many cases this only requires thewithdrawal of a small amount of blood from the body in the form of ablood drop by producing a small puncture wound. A particularly importantexample of such a case is diabetes in which the glucose content of bloodhas to be examined at regular intervals. Blood may also for example beexamined with regard to coagulation parameters, triglycerides, HbA1c orlactate. Blood lancet devices which consist of a lancing device andtailor-made replaceable lancets are usually used to produce the requiredpuncture wounds. A lancet holder in which one interchangeable lancet canbe inserted is present in the housing of the lancing device. During thelancing operation the lancet holder is rapidly moved in a lancingdirection by a lancet drive which is also integrated into the lancingdevice until the lancet tip emerges from an exit opening provided at thefront end of the lancing device and produces a small puncture wound inthe part of the body that is pressed against the front end. Afterwardsthe lancet holder containing the lancet is moved back in the oppositedirection to the lancing.

Small, easy to handle blood collection devices, so-called lancing aidsthat can be easily and reliably operated by the user and enable a partof the body to be lanced in a manner that is as pain-free as possibleare now routinely used. In order to avoid infections especially inhospitals, the lancets are disposable elements intended for single use.After a lancet has been used once, the lancet is removed after thelancing operation or ejected from the device and discarded as refuse. Insuch a case the exposed lancets in a refuse container may lead to injuryduring waste disposal which may result in a contamination of otherpersons by the used lancet. Such contamination may lead to infectionsand thus some countries are planning to impose a ban on blood collectionsystems in which the needle tip is freely accessible after use. Inaddition to a risk of injury during waste disposal, there is also a riskthat a used lancet may be accidentally re-used. This is particularlyrelevant for hospitals in which a lancing aid is used for severalpatients since such inadvertence of the nursing staff could lead to apatient being contaminated with the blood of a previous patient.

In addition to the use of blood lancet devices by medical staff, lancingaids are also used by laymen in the so-called home-monitoring field.This is particularly the case for monitoring the treatment of diabetics.Thus, it has been found in the treatment of diabetics that seriousdamage associated with diabetes such as loss of sight can besubstantially reduced when the glucose concentration in the blood of thediabetic is determined frequently and up to five times daily and theinsulin injection is exactly adjusted on the basis of thesemeasurements. Lancing aids which enable the diabetic to carry out such ablood examination by himself are used for home-monitoring in order tocarry out such frequent measurements. The resulting requirements for ablood lancet device are a simple handling when inserting new lancets anda reliable ejection of used lancets in addition to a simple handlingwhen triggering the lancing operation and a relatively painlesspuncture. Lancet replacement should on the one hand be as simple aspossible and, on the other and, ensure the utmost safety with regard tounintentional injury of the user or other persons. Although in thehome-monitoring field it is conceivable that a lancet, once inserted, isused several times for lancing by the same user, even in this case anaccidental re-use of an ejected lancet should be prevented once the userhas decided to discard the lancet. Furthermore, other persons inparticular should be reliably protected from the discarded lancets forexample during waste disposal.

In the prior art the tip of the lancet is usually surrounded by a tipcover made of plastic when the lancet is inserted which allows a safehandling when the lancet is inserted. When the lancet is inserted, thetip cover is removed to expose the sharp tip of the lancet for thelancing operation. See, e.g., U.S. Pat. No. 5,628,765. However, due tothe exposed lancet tip there is a risk of accidental injury and the tipmay become damaged. The lancet is removed from the lancing aid after oneor several lancing operations. This can either be carried out manuallyin which case there is a high risk of injury by the lancet tip or by anautomatic ejection mechanism.

A blood lancet device is disclosed in EP 0 565 970 in which the lancetis ejected from the lancet holder by means of an ejecting rod. The usercan operate the ejecting rod by pressing a corresponding button.

Furthermore, an ejecting mechanism is described in the patent documentU.S. Pat. No. 4,442,836 where the lancet is automatically released whenthe lancing aid is retensioned so that the used lancet is discardedafter each lancing operation. Such ejecting mechanisms require arelatively high degree of additional engineering. Moreover, multiple useof an already inserted lancet system is not possible, which is, however,often desired by customers especially in the home-monitoring field.Another major disadvantage of the described prior art is that the lancettip is unprotected after the lancet has been ejected resulting in anassociated risk of injury as described above.

In order to facilitate the safe removal of a used lancet, bloodcollection systems are also described in the prior art which ensure thatthe lancet tip is protected after ejecting the lancet. This is regardedas an essential feature especially for elderly users or those who arehandicapped by poor sight and shaky or trembling hands as a result ofdisease.

A protection of the lancet tip is achieved in the prior art byintegrating the lancet in a cap of the lancing aid such that the lancetand the housing cap together form a replaceable disposable unit. Suchdesigns are described in the documents EP 0 595 148 and U.S. Pat. No.4,990,154, U.S. Pat. No. 5,454,828 and U.S. Pub. No. 2004-0034318. Whenthe lancet is ejected by the user, the housing cap is placed over thelancet tip so that the lancet surrounded by the cap can be subsequentlydiscarded. Even if the lancet tip is protected after ejection by thedescribed mechanism, it is nevertheless possible for a careless user toreinsert a lancet that has already been ejected once and carry out a newlancing operation. Consequently the user himself has to recognize thatthe lancet has already been used.

The document EP 0 630 609 discloses a mechanism which directly preventsreinsertion and thus re-use of a lancet that has been ejected once. Thedescribed lancet device comprises a lancet with a lancet body whichbreaks when the lancet is ejected from the lancing aid to prevent areinsertion of the lancet. This prevents the user from re-using acontaminated lancet. However, a disadvantage of the prior art is thatthe lancet tip is unprotected after the lancet has been ejected.

For individual lancets there are a wide variety of solutions forprotecting a user from the used lancet tip. Thus, various mechanisms aredescribed in the documents U.S. Pat. No. 5,964,731, U.S. Pat. No.7,001,364 and U.S. Pat. No. 5,454,828 relating to how a protectingmechanism can be brought over the lancet after use so that the lancetcannot be re-used. However, these mechanisms either have to be appliedby the user himself which limits the effectiveness of the protectionfrom injury or the mechanism is automatically triggered after eachlancing operation by the lancing mechanism of the lancing aid asdescribed in WO 2008/072414 so that the lancet can only be used once inan inserted state.

A protection against re-use is described in U.S. Pat. No. 7,785,338which enables the housing of the lancet system to be changed after useof a lancet system in such a manner that it can no longer interact in aregular manner with a lancing aid. This is achieved by a change in thecoupling site between the lancet magazine and lancing aid. In this caseit is no longer possible to reinsert an already used magazine. This isintended to protect the user against re-using an already used lancet.However, a disadvantage of this prior art is that the coupling site ofthe lancing aid can be damaged when it is attempted to reinsert analready used magazine into the lancing aid if the user does notimmediately recognize that the magazine no longer correctly fits thecoupling site of the lancing aid.

SUMMARY

The present invention provides an easy to handle lancet magazinepreferably for the home-monitoring field which can interact with alancing aid in such a manner that the re-use of an already ejectedlancet magazine is prevented, without affecting the interaction of thelancet magazine and the lancing aid and at the same time ensuring at alltimes a protection from injury from the lancet tip when the lancetmagazine is used. Multiple use of a lancet of a lancet magazine that hasbeen inserted only once is advantageously possible.

The embodiments disclosed herein concern a lancet magazine and a lancetsystem having a lancing aid and a lancet magazine. Also disclosed is asecuring system for securing the lancets in the lancet magazine or thelancet system.

The lancet magazine for use in a lancing aid comprises a housing havinga distal and a proximal end and at least one cavity for storing lancets.A plurality of lancets each having a lancet body at the proximal end ofthe lancet and a lancet tip at the distal end of the lancet which issuitable for generating an opening in the skin, are located in thelancet magazine. The proximal end of at least one lancet points in thedirection of the proximal end of the housing and the distal end of thelancet is aligned in the direction of the distal end of the housing. Theproximal end of the lancet magazine housing is preferably designed suchthat it can interact with a lancing aid. This interaction can becharacterized by the magazine holder or by the design of the proximalend allowing entry of a drive element of the lancing aid, e.g., in theform of an opening or recess in the lancet magazine housing. The lancetsare completely surrounded by the housing in the unused state. Thisensures that whenever the lancet magazine is used the user cannot beinjured by the lancets. The lancet is only moved into a deflected stateby the drive mechanism of the lancing aid and can puncture the skin ofthe user when it is in the withdrawal position.

Furthermore, the lancet magazine has an extension unit which is movablyconnected to the housing of the lancet magazine. The extension unit canmove in the direction of the distal end of the magazine housing suchthat the housing can be extended by the extension unit in the directionof the distal end of the housing and can thus prevent the lancet fromemerging from the lancet magazine. As a result the lancet does notemerge from the lancet magazine even when a lancing mechanism istriggered and even if the lancet magazine is correctly inserted into thelancing aid. There is preferably a lancet in each cavity. The cavitiescan be separated from one another by cavity walls. It is, however, alsoconceivable that the cavity is the void around each lancet and that theyare only separated from one another by a groove or notch on the lancetmagazine. The cavity may also be a hollow space in which at least twolancets are located which are at a defined distance from one another.After the lancet magazine has been extended, the lancet cannot emergefrom the extended lancet magazine housing even if the lancet magazinehas been correctly coupled with the lancing aid.

Consequently the lancet magazine has two elements which areinterconnected in such a manner that they can move relative to oneanother. The elements are the lancet magazine housing itself and theextension unit. These two elements are arranged relative to one anotherin such a manner that the lancet magazine can be selectively convertedfrom an unextended state into an extended state. There are noconstraints on the shape and design of the two elements provided theyare arranged movably in relation to one another such that in theunextended state at least one of the lancets in the lancet magazinehousing can be at least partially moved out of the lancet magazinehousing and that in the extended state of the lancet magazine the lancetcannot emerge from the lancet magazine. During the extension process theextension unit is preferably moved parallel to at least one lancet inthe lancet magazine. This is the lancet which is located in a removalposition in the lancet magazine or lancet system. This removal positionis defined relative to the lancet magazine such that the lancet magazinehousing has an opening at the distal end through which the lancet canpass. In relation to a lancing aid into which the lancet magazine can beinserted, the removal position is characterized such that a driveelement (e.g., a plunger) can interact with one of the lancets in thelancet magazine such that this lancet is movably supported in the lancetmagazine for a lancing operation. The extension of the lancet magazinein the direction of the longitudinal axis of the lancet in the removalposition ensures that the lancet cannot emerge from the lancet magazineeven when it is deflected by a lancing aid.

The extension unit as well as the lancet magazine housing can bemanufactured from plastic material but other materials such as sheetmetal are also conceivable. The lancet magazine housing preferably has adrum-like shape. Other shapes such as cuboid, cylindrical or disk-shapedstructures are also conceivable. In this case the lancet magazine has atleast one opening which allows at least one lancet to emerge from thelancet magazine housing during a lancing operation in the unextendedstate of the lancet magazine. In this process at least part of thelancet but at least the lancet tip protrudes from this opening. Theextension unit which is movably connected to the lancet magazine housingat least in the area of the opening is located around at least part ofthe lancet magazine housing either within or outside the lancet magazinehousing. It can be connected by means of guide grooves. The extensionunit is preferably located outside the lancet magazine housing andmatches the shape of the lancet magazine housing in at least twodimensions. In this connection the extension unit has a form fit withthe lancet magazine housing. Furthermore, the movement of the extensionunit is restricted in both directions of movement to prevent theextension unit from unintentionally slipping from the lancet magazinehousing. This restriction can, on the one hand, be achieved by guideelements such as a groove and notch whose shape and lengths are matchedto one another in such a manner that movement along one axis isrestricted. On the other hand, the extension unit can be tapered at oneend relative to the dimension of the lancet magazine housing so that arestriction of movement is achieved by the tapering. Since the aim is tobe able to align or move the extension unit selectively relative to thelancet magazine housing such that the lancets do not emerge from thelancet magazine in the extended state even when they are deflected, itshould be possible to move the extension unit at least in the directionof the opening of the lancet magazine housing in order to prevent thelancet from emerging from the lancet magazine in the removal position inthe case of an intentional or unintentional lancing operation. Theextension unit preferably has a length in its dimension in the directionin which the extension takes place which corresponds to at least thelength of the part of the lancet which comes out of the lancet magazinehousing during a regular lancing operation. However, the extension unitmay also be longer. However, at least the length of the exiting part ofthe lancet should be covered by the extension unit in the extended stateduring a normal lancing operation.

Consequently, the lancet magazine is rendered unusable by the movementof the extension unit and at the same time the user is additionallyprotected against unintentional puncturing because the lancets arecompletely surrounded by the lancet magazine. The extension of thelancet magazine in the distal direction ensures that the proximal sideof the magazine that can interact with a lancing aid is not impaired.This prevents reuse of the lancet magazine after extension of themagazine without impairing the insertion of the magazine. This has theadvantage that if a used lancet magazine is accidentally inserted intothe lancing aid, the docking site between the lancet magazine andlancing aid is not impaired. This prevents the lancing aid, which shouldbe available for many years for the user, from being manipulated ordamaged by a modified lancet magazine and rendered unusable, as is thecase in EP 1 459 683 (U.S. Pat. No. 7,785,338) in which the lancetmagazine is modified at the proximal end of the magazine to preventreinsertion.

The extension unit can be moved automatically when the magazine isremoved from the lancing aid. This can for example be carried out bymeans of an automatic ejection mechanism of the lancing aid which isactuated by the user once the magazine has been consumed. However, theextension unit can also be moved manually by the user along the lancetmagazine when the magazine is manually removed from the lancing aid. Inthis case the lancet magazine housing and the extension unit areconnected together in the unextended state such that the extension unitcan only be transferred into the extended state when a certainapplication of force has been exceeded. This can for example be achievedby means of the fact that parts of the lancet magazine housing and ofthe extension unit are so closely mounted together that a certainfrictional force has to be overcome until it is possible to move theextension unit. This securing of the unextended state can alternativelybe accomplished by elements on the lancet magazine housing and extensionunit such as for example notches or projections which rub against oneanother or hook into each other or lock into each other. A similarlocking also takes place in the extended state of the lancet magazine.

In one embodiment the magazine can be inserted into the lancing aid insuch a manner that the user can also remove the magazine withoutactuating the extension mechanism. This enables the user to also removea lancet magazine from the lancing aid which has not been completelyused up without it being made unusable by the extension. This can beachieved either by means of the fact that the extension unit extendswithin the lancet magazine housing and only protrudes from the distalend of the lancet magazine housing and can then be gripped in order tocarry out the extension process. In an alternative embodiment the lancetmagazine housing can be stretched out such that it is mounted in theinserted state within a lancing aid in such a manner that it can begripped by the user so that the user is not able to handle the extensionunit in order to remove the lancet magazine from the lancing aid andthus trigger the extension mechanism but can rather grip the lancetmagazine housing itself and remove the lancet magazine without using theextension mechanism.

Furthermore, it is possible to use the lancet which is located in thecollecting position in the lancet system several times. Hence, the usercan select how often he uses each lancet before he moves a new lancetinto the collecting position, e.g., by advancing the magazine in thelancing aid. However, the extension process can also be carried out onthe lancet magazine without the magazine being inserted into the lancingaid.

The lancet magazine can also be inserted at any time into the lancingaid even in the extended state. In this case the proximal end of thelancet magazine housing can be inserted into the lancing aid to enable acorrect interaction between the lancing aid and magazine. The lancingoperation as such in which the drive unit interacts with the lancet andmoves the lancet within the lancing aid can be also executed without,however, the lancet emerging from the lancet magazine.

The extension unit may interact with the housing after it has moved inthe distal direction relative to the housing of the lancet magazine,i.e., in the extended state so that it cannot again be manually moved inthe proximal direction of the housing. This can be achieved by a lockingbetween the extension unit and lancet magazine housing. Interaction oftwo notches or of a groove and notch, one on the extension unit and oneon the lancet magazine housing, are examples of such a locking of thetwo elements. This prevents the extension unit from moving again byitself into its original length in the unextended state.

These teachings additionally concern a lancet system for carrying out alancing operation in a body comprising a lancing aid with a housing anda drive mechanism for a lancet as well as a receiving opening for alancet magazine, a lancet magazine with a housing, which has a distaland a proximal end, comprising at least one lancet, the lancet having atip at its distal end and its distal end pointing in the direction ofthe distal end of the lancet magazine, an extension unit which ismovably connected to the housing of the lancet magazine.

The lancet magazine can be extended by the extension unit in thedirection of the distal end of the housing thus preventing the lancetsfrom emerging from the lancet magazine when it interacts with thelancing aid. In this process the proximal end of the lancet magazine isinserted into the lancing aid because the proximal end of the magazineis preferably designed so that it can interact with the lancing aid insuch a way that it is held.

An aspect of these teachings is a lancet magazine that can be removedfrom the drive unit and which contains at least one lancet, the lancetmagazine being provided as a disposable unit. In this connection theterm lancet encompasses a blade-shaped, flat lancing unit as well asother conceivable embodiments. In principle lancets as they arebasically well-known in the prior art and are used in lancet systems canbe used within the scope of these teachings. In this connection acombination of a lancet with a base body which can couple to the lancingaid is frequently referred to as a lancet in the prior art. Such lancetsoften have a base body made of plastic in which a metal lancet isdisposed. According to these teachings it is possible to integrate sucha lancet into the lancet magazine or system. It is for exampleconceivable that the lancet body contains a base body like that used forlancets in the prior art, where the inventive functionality of thesystem is maintained by integration of the base body. In this case thelancet body has an at least two-part design according to the describedembodiment. The lancet and the base body can then be guided in a movablemanner within the magazine. The lancets within the lancet magazine canbe present in separate cavities in order to prevent contamination ofunused lancets by used lancets when reloading.

In order to carry out a lancing operation, portions of the lancet bodyare advantageously designed like the system already described in U.S.Pub. No. 2004-0034318 such that the individual lancets of the system canbe actively coupled to the drive unit of the lancing aid. Embodimentsthat can also be used to drive lancets within a magazine of a lancingaid are described for example in the documents DE 10053974, U.S. Pat.No. 4,990,154 and U.S. Pat. No. 5,074,872. The chambers arranged next toone another in which the lancets are individually located are positionedsuccessively relative to the drive unit in order to carry out a lancingoperation in such a manner that in each case a single lancet can becoupled to the plunger of the drive unit. Also in this case, magazinesin the form of a drum containing chambers in which the lancets arelocated parallel to the longitudinal axis of the drum have also provento be particularly advantageous. The lancets preferably have additionallancet body arms on their lancet body which can interact with the driveunit of the lancing aid in such a manner that a form-fitting connectioncan take place between the drive unit (e.g., in the form of a plunger)and the lancet so that a guided movement of the lancet can take placeduring the lancing operation.

The lancet system can comprise a lancing aid with an attachable capwhich can be removably connected to the housing of the lancing aid.After the extension operation of the lancet magazine by movement of theextension unit relative to the lancet magazine housing in which theextension unit is moved in the direction of the distal end of thehousing of the lancet magazine, the cap can no longer be properlyconnected to the housing of the lancing aid. This is a furtherindication for the user of the lancing aid that the lancet magazine thathe wants to use in the lancing aid has already been used.

In addition, a method for avoiding reuse of a lancet magazine isdescribed in which the unused lancet magazine containing at least onelancet is placed in a lancing aid where the lancet magazine can again beremoved from the lancing aid and a movable extension unit on the lancetmagazine is moved in the direction of the distal end of the lancetmagazine.

The lancets in the lancet magazine can be secured by securing meansagainst a movement relative to the lancet magazine housing caused byaccidental application of force. Such an accidental application of forcecan for example be that the lancet magazine alone is dropped or isdropped in combination with a lancing aid in which the lancet magazineis fitted.

This securing means can for example be a plastic sheath around thelancet tip. This sheath can be pierced when sufficient force is exertedon the lancet by a lancing aid.

This sufficient exertion of force occurs for example during a normallancing operation in which the drive unit of the lancing aid, e.g., inthe form of a plunger, is moved onto the lancet and the tip of thelancet is driven out of the housing of the lancing aid by this forceimpact in a guided movement. In contrast, the force exerted when alancet magazine drops from a height of for example 2 m is not sufficientto pierce the plastic material. The threshold at which the force exertedis sufficient to pierce the plastic can be influenced by the selectionof the composition of the plastic. U.S. Pub. No. 2003-0153939 describeshow such a plastic can be constructed and how it can be connected to thelancet in such a manner that it fulfills the function of a sterileprotection as well as a means for securing the lancet in the case of afall.

In addition, the lancet system can also have a lancet holder forsecuring lancets in a lancet magazine in which case the lancing aid hasa cavity for receiving a lancet magazine, and the lancing aid has aremoval position in which a drive element can interact with one of thelancets in the lancet magazine such that this lancet is movablysupported in the lancet magazine for a lancing operation. In thisconnection the lancing aid additionally has a securing element whichprevents movement of the lancets which are not positioned in thecollecting position. This securing element is preferably designed in theform of a pin which at least partly penetrates into the lancet magazinewhen the lancet magazine is inserted into the lancing aid. When thelancet magazine is inserted into the lancing aid, this pin is positionedrelative to the lancet magazine in such a manner that the lancet bodyarms of the lancets which are not in the collecting position are securedin a recess of the lancet magazine housing. The lancet which is in thecollecting position is for example secured by the plunger of the driveunit of the lancing aid by means of the fact that the lancet body armsand the plunger make a form-fit. The pin preferably has an elongate penshape and thus advantageously has a round shape. Due to the round shapeit creates less resistance when the lancet magazine is inserted into thelancing aid. The selective securing of only the lancets that are not inthe collecting position is for example accomplished in that the pin isat least partly asymmetrically inserted into the lancet magazine.Alternatively the pin can have a recess for the drive element of thelancing aid which is moved parallel to the pin in the housing of thelancing aid during the lancing operation. This securing means protectsthe lancets in the lancet system or in the lancet magazine fromunintentional displacement. An unintentional displacement of the lancetswould for example be that the lancing aid together with the lancetmagazine is dropped. Falls from greater heights, e.g., from up toheights of 3 m can be absorbed by this mechanism without the risk that alancet accidentally emerges from the lancing aid or the lancet magazine.As a result the risk of injury due to incorrect operation of the lancingaid is largely eliminated.

One feature of the lancet system is the sterility of the lancet tipwhich is provided to produce a wound in an appropriate part of the body.The sterility of the lancet tip has to be ensured over a long periodwhich extends from the manufacture of the lancet system up to its use.Sterility can be achieved during the manufacture of the lancet system byfor example gamma radiation which is commonly used in the prior art. Inorder to maintain sterility, the lancet system can be sealed in awrapping for example a polyethylene bag. In another embodiment theopening of the lancet system where the lancet tip emerges from theprotective portion of the lancet body can for example be closed by asealing foil. These are preferably detachable sealing foils which theuser removes before using the lancet system. However, it is alsopossible to use thin foils which are not pierced by the lancet tip untilthe lancet is used so that the user does not have to carry outadditional handling steps. Such foils may already be used as an integralpart of the manufacturing process for the lancet system which is usuallyby means of an injection molding process.

Furthermore, in the prior art an elastomer is described in theapplication WO 01/66010 for sterile protection which encloses the lancettip and thus protects it against contamination. This sterile protectioncan either be pierced during the lancing operation or be removed by theoperator before use.

In an advantageous embodiment the protective portion of the lancet bodycan comprise a sterile protection and/or the protective portion can beessentially formed thereby. In this case the elastomer of the sterileprotection itself serves for example as the protective portion of thelancet body by the fact that the lancet tip can be moved in a guidedmanner relative to the elastomer. In this process the sterile protectionreversibly exposes the lancet tip or surrounds it again as for examplein the case of an elastomer protection (US Pub. No. 2003-0153939) inwhich the elastomer is firstly pierced during the lancing operation andsubsequently the lancet tip is retracted into the elastomer.Consequently in this example the lancet tip changes its positionrelative to the sterile protection during the lancing operation and thelancet tip is protected in its resting position after the lancingoperation. In principle many embodiments of a sterile protection areconceivable and hence the inventive system is not limited to any specialembodiment of a sterile protection.

DESCRIPTION OF THE FIGURES

The above-mentioned aspects of the present invention and the manner ofobtaining them will become more apparent and the invention itself willbe better understood by reference to the following description of theembodiments of the invention, taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1A is a side view of a lancet magazine with an extension unit inthe unextended state;

FIG. 1B is a side view of the lancet magazine of FIG. 1A with anextension unit shown in the extended state;

FIG. 2A is a longitudinal sectional view of the lancet magazine of FIG.1A taken along line B-B;

FIG. 2B is a sectional view of the lancet of FIG. 1A taken along lineB-B and showing the lancet magazine in the extended state;

FIG. 3A is a sectional view of the lancet magazine from FIG. 2A along aline of intersection A-A;

FIG. 3B is a sectional view of the lancet magazine from FIG. 2B in alongitudinal section along the line of intersection A-A from FIG. 2B;

FIG. 4A is a sectional view of a lancet magazine fitted into a lancingaid which has a removable protective cap in a non-extended state in alongitudinal section along the line of intersection A-A;

FIG. 4B is a longitudinal sectional view along the line of intersectionA-A of a lancet magazine in an extended state fitted into a lancing aidwith a removable protective cap where the protective cap no longer latchwith the lancing aid;

FIG. 5A is a side view of a lancing aid with a finger cap which iscorrectly locked into place because the inserted lancet magazine is notin an extended state;

FIG. 5B is a longitudinal section through a lancing aid from FIG. 5Awith a finger cap and inserted lancet magazine in a non-extended statealong the line of intersection A-A;

FIG. 5C is a longitudinal section of a lancing aid with an insertedlancet magazine after extension and attached finger cap which cannot becorrectly locked with the lancing aid (line of intersection A-A); and

FIG. 5D is a side view of a lancing aid with a finger cap which cannotlatch with the lancing aid because the lancet magazine is in an extendedstate.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

The lancet magazine (7) shown in FIGS. 1 to 5 has a cylindrical shapewhich, however, does not mean that the magazine cannot also have anyother shape, such as for example a box-like or cuboid shape. Thecylindrical shape of the lancet magazine (7) shown here enables thelancets to be stored in the longitudinal direction of the cylindricalhousing (1). Hence, the lancets lie parallel to one another in thehousing (1).

FIG. 1A shows a lancet magazine (7) with a housing (1) which completelyencloses the stored lancets (not shown in FIG. 1A). The lancet magazine(7) has an opening (30) at one end (the proximal end) through which alancing aid (not shown in FIG. 1A) can interact with the lancets in theinside of the lancet magazine (7). There is likewise at least oneopening (40) on the opposite side (the distal end) of the lancetmagazine (7) which enables a lancet to exit from the magazine (7) duringthe lancing operation. The lancet magazine (7) additionally has anextension unit (2) which is movably connected to the housing (1). Thisextension unit (2) preferably also has a cylindrical design and islongitudinally aligned parallel to the housing of the lancet magazine(2) where at least part of this extension unit movably interacts withthe housing (1). In the embodiment of FIGS. 1 and 2 the extension unit(2) spans a part of the lancet magazine housing (1) in its longitudinalextension and protrudes from the lancet magazine housing (1) at thedistal end of the lancet magazine housing (1). This distal end of theextension unit (2) has a handle edge (2 a) which is in the form of athickening of the cross-section of the extension unit (2). Furthermore,the extension unit (2) has at least one lateral slot (5) and at leastone guide (6) on its longitudinal side. The side slot (5) serves toreceive a latch arm (4) which is attached to the lancet magazine housing(1). The latch arm (4) moves during the process of extending the lancetmagazine housing (1) through the extension unit (2) from the distal endof the side slot (5 a) to the proximal end of the side slot (5 b) sothat the latch arm (4) prevents the extension unit (2) from being movedfurther beyond the lancet magazine housing (1). Hence, it limits theextension displacement so that the extension unit (2) cannot becompletely removed from the lancet magazine housing (1). Consequentlythe latch arm (4) can be seen at the upper (distal) end of the side slot(5 a) in FIG. 1A, whereas after extension of the lancet magazine (7) itis found in FIG. 1B at the proximal end of the side slot (5 b).Furthermore, the extended lancet magazine (1) from FIG. 1B has anoptical mark (50) in the form of letters. This optical mark (50) can,however, also be designed in the form of a colored mark preferably onthe lancet magazine housing (1).

A cross-section of the lancet magazine (7) from FIG. 1A is shown in FIG.2A in the line of intersection B-B. This view shows the arrangement ofthe latch arm (4) within the lancet magazine housing (1) where one endof the latch arm protrudes out of the side slot (5) of the extensionunit (2). An additional latch arm (4 a) is attached to another positionof the lancet magazine housing (1) and is arranged within the extensionunit (2). This latch arm (4 a) has a notch (4 b) which can interact withthe notch (2 b) of the extension unit (2) during an extension operationof the lancet magazine housing (1) in such a manner that the lancetmagazine housing (1) can no longer be shortened as shown in FIG. 2B. Inthis case this is achieved by beveling the notches (4 b) and (2 b) inopposite directions so that these two elements are locked together in aform-fitting manner. The magazine housing (1) and extension unit (2) canalso interact in other ways to prevent a return movement after theextension phase. Thus, it would also be conceivable that the notch (4 b)engages in a groove of the extension unit (2) and is locked intoposition there. During the extension process, the inner latch arm (4 a)is pressed by the notch (2 b) into the inside of the lancet magazineuntil the notch (5 b) has slid past the notch (4 b). When the twonotches slide past each other a certain frictional resistance is builtup which has to be overcome during the extension process. This ensuresthat the lancet magazine (7) does not become extended by itself or by asmall exertion of force in its longitudinal direction by moving theextension unit (2) against the lancet magazine housing. Although theinserted lancets (8) cannot be completely seen in this view of FIGS. 2Aand 2B because they are covered by a cavity boundary (3 a), it is atleast possible to see the lancet body arms (8 c) of two lancets (8)below the cavity boundaries (3 a).

FIG. 3A shows the stored lancets (8) with the lancet tips (8 a) as wellas the lancet bodies (8 b) and the lancet body arms (8 c) in thesectional plane A-A of FIG. 2A. In addition a sterile protection (9)which surrounds at least the lancet tip (8 a) is shown in this sectionalview. This sterile protection (9) serves to keep the lancet tip (8 a)sterile during the storage phase and can be held back by the lancetopening (40) during the drive operation of the lancet (8) wherein aplunger of the lancing aid can interact with the lancet body arm (8 c)and move the lancet (8) towards the opening (40) of the lancet magazineso that the lancet tip (8) is exposed for the lancing operation. Thissterile protection (9) can additionally undertake the function ofsecuring the lancets (8) in the lancet magazine (7) while the lancetmagazine (7) is in use, i.e., is inserted into a lancing aid but alsooutside a lancing aid. In this connection the sterile protection (9)secures the lancets (8) against unintentional protrusion from theopenings (40) when a small force is exerted, e.g., by dropping thelancet magazine (7).

FIG. 3B shows the lancet magazine (7) after the extension process wherethe lancet tip (8 a) of the lancet (8) at maximum excursion does notproject from the lancet magazine (7). The maximum excursion is forexample reached during the regular drive of the lancet (8) in a lancingaid (not shown here) as is carried out for a common lancing process inorder to puncture the skin of a patient for blood collection.

This state is shown in FIG. 4B in which the lancet magazine (7) is shownintegrated into a lancing aid (15) after the lancet magazine housing (1)has been extended. In this case it is indeed possible to correctlycouple the lancet magazine (7) to the housing (10) of the lancing aid(15) which means that the means for locking together the lancet magazine(7) and lancing aid (15) are not impaired. It is also still possible tocouple the plunger (11) so that the lancet (8) is moved within thelancet housing (1) to the distal end of the lancet magazine (7 a) butcannot emerge from the lancet magazine that has been extended by theextension unit (2) and consequently no lancing operation can beexecuted. However, in this embodiment it is not possible to attach thefinger cap (20) in such a manner that the housing of the lancing aid(10) can lock with the finger cap (20).

This is different in the non-extended state of the lancet magazine (7)which is correctly incorporated into a lancing aid (15) as shown in FIG.4A. In this case the lancet magazine (7) is also inserted and centeredin the lancing aid (15) by means of a pin (12) so that the plunger (11)can interact in a lancing operation with the lancet via the lancet bodyarm (8 c) in such a manner that the lancet (8) in the magazine is movedin a guided manner and the lancet tip (8 a) is moved out of the lancingaid (15) through the opening (21) of the finger cap (20). In this casethe pin (12) is inserted in such an asymmetric manner into the lancetmagazine (7) that it does not impede the movement of the plunger (11)with the lancet (8) that is currently located in front of the opening ofthe finger cap (21), but protects all other lancets (8) in the magazineagainst unintentional movement. This movement protection is achieved inthat the lancet body arms (8 c) of the other lancets (8) are located ina groove (13) of the lancet magazine (1) (or alternatively between thelancet magazine (1) and lancing aid (15)). The pin projects beyond apart of the lancet body arms (8 c) to such an extent that even whenforce is exerted on the lancing aid (15) or onto the lancet magazine(7), the lancets (8) cannot shift from their position because the lancetbody arm (8 a) is clamped in the groove (13) between the pin (12) andthe lancet magazine housing (1).

FIGS. 5A to 5D show the lancet magazine (7) incorporated in a lancingaid (15) with an attached finger cap (20) in the unextended state of thelancet magazine (7) in FIGS. 5A and 5B and in the extended state of thelancet magazine (7) in FIGS. 5C and 5D. The lancing aid (15) with aproperly attached finger cap (20) is shown in Fig. A where the fingercap (20) is locked with the housing (10) of the lancing aid (15) in sucha manner that it optically forms one unit. A section along the line ofintersection A-A of this assembled lancing aid (15) is shown in FIG. 5B.This in turn shows that the lancet magazine (7) interacts with thelancing aid (15) in such a manner that the plunger (11) of the lancingaid (15) can be brought into contact with the lancet body arm (8 c) insuch a manner that the tip (8 a) of the lancet (8) can emerge in aguided manner from the opening (21) of the lancing aid (15) or thefinger cap (20).

FIGS. 5B and 5C show the state in which an extended lancet magazine (7)is inserted into a lancing aid (15) where the magazine (7) can interactwith the lancing aid (15) but the finger cap (20) can no longer becorrectly placed on the lancing aid. This is shown particularly well inFIG. 5D because the depression in the housing (10) of the lancing aid(15) is exposed and is not reached by the finger cap (20) so that only aloose connection between the finger cap (20) and lancing aid (15) isachieved which does not hold when the lancing aid (15) alone is grippedin its housing (10) and held in the direction of the distal end (7 a).In this state it becomes apparent to the operator that the magazine (7)cannot be correctly assembled with the lancing aid (15) including thefinger cap (20) and must consequently have been used.

While exemplary embodiments incorporating the principles of the presentinvention have been disclosed hereinabove, the present invention is notlimited to the disclosed embodiments. Instead, this application isintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

LIST OF REFERENCE NUMERALS

-   1 housing of the lancet magazine-   2 extension unit-   2 a grip edge-   2 b notch on extension unit-   3 a cavity boundary-   4 latch arm-   4 a latch arm inside 10 4 b notch on latch arm-   5 side slot-   5 a distal end of side slot-   5 b proximal end of side slot-   6 guide-   7 lancet magazine-   7 a distal end (lancet magazine)-   7 b proximal end (lancet magazine)-   8 lancet-   8 a lancet tip-   8 b lancet body-   8 c lancet body arm-   9 sterile protection-   10 housing of lancing aid-   11 plunger-   12 pin-   13 groove-   15 lancing aid-   20 finger cap-   21 opening of finger cap-   23 depression-   30 proximal opening of lancet magazine-   40 distal opening of lancet magazine-   50 optical mark

What is claimed is:
 1. A method for avoiding re-use of a lancetmagazine, comprising; (a) inserting a lancet magazine having a pluralityof lancets into a lancing aid; (b) performing at least one lancingoperation with at least one lancet of the plurality of lancets; (c)removing the lancet magazine from the lancing aid; and (d) moving anextension unit of the lancet magazine into an extended state whichincreases the length of the lancet magazine and thereby prevents thelancets from emerging from the lancet magazine.
 2. The method of claim1, wherein step (d) is executed automatically during step (c).
 3. Themethod of claim 1, further comprising reinserting the lancet magazineinto the lancing aid after step (d) without impairing the lancing aid.4. The method of claim 3, wherein the extension unit remains in theextended state during the reinserting of the lancet magazine into thelancing aid.
 5. The method of claim 4, further comprising, after thelancet magazine has been reinserted into the lancing aid, triggering alancing mechanism of the lancing aid and thereby moving one of thelancets within the lancet magazine.
 6. The method of claim 1, whereinstep (d) comprises locking the extension unit in the extended state. 7.The method of claim 6, wherein the locking is done via notches locatedon the extension unit and a housing of the lancet magazine.
 8. Themethod of claim 6, wherein the locking is done via a groove located onone of the extension unit and a housing of the lancet magazine and anotch located on the other of the extension unit and the housing.
 9. Themethod of claim 1, wherein step (d) occurs while a user manually removesthe lancet magazine from the lancing aid.
 10. The method of claim 1,further comprising providing the extension unit and a housing of thelancet magazine as cylindrically shaped and movably connected to oneanother.
 11. The method of claim 10, wherein the extension unit and thehousing are provided as a concentric arrangement and the housing fits atleast partially within the extension unit.
 12. The method of claim 1,wherein step (d) causes a housing of the lancet magazine to extend fromthe extension unit.
 13. The method of claim 1, further comprisingaligning the extension unit and the housing parallel to one another. 14.The method of claim 13, wherein the extension unit and the housingremain parallel to one another during step (d).